Genki Terauchi on Ocean Colour Remote Sensing, Seagrass & the Shape of Waves
By N. Miyazaki
“It was easy to access from work, and I loved the shape of the waves that place used to create”, this is how Genki Terauchi - a scientist with the UNEP Action Plan for the Protection, Management and Development of the Marine and Coastal Environment of the Northwest Pacific Region’s Special Monitoring & Coastal Environmental Assessment Regional Activity Centre (NOWPAP CEARAC) - reminisces about Kanaiwa beach in Kanazawa. A beach he spent a lot of time surfing at after graduating from Hosei University where he majored in Architecture. “Wave shape is determined by bottom topography...and other factors”.
At that time, he was working in computing for a company called I-O Data Device, Inc., that specializes in high-quality computer peripherals and interface products. A company he spent a few years with before coming across a job posting in the Japan Times looking for someone that spoke English, was good with computers, and was willing to travel a lot within the Arctic Circle. He took the job. When I asked him what appealed to him about it, he replied - “excitement”.
The job landed him at the Earth Observation Center of JAXA in Saitama Prefecture and other overseas ground stations located in the Arctic where he coordinated works to receive satellite signals from space to ground, but six months into the job there was an anomaly with the satellite they were working with, and after a further six months, the project was cancelled. While the option for him to stay was left open, he chose to return home instead. “I got tired you know, just sitting behind a desk”.
It was not long after this that his first daughter was born and he found himself at the beginning of his career with CEARAC. “There was no ad, I just called NPEC from the hospital the moment I heard the baby cry”. NPEC is the Northwest Pacific Region Environmental Cooperation Center based in Toyama, Japan - they share a Memorandum of Understanding with UNEP, and have hosted CEARAC since it was established in 1999. “I wanted a job by the ocean”, he said, “and the timing was also really good” he recalled with a laugh. A former employee was leaving, which made available a position.
Terauchi grew up in a city called Kahoku, in Ishikawa prefecture. A guidebook published by the prefecture describes it as a city “ blessed with beautiful nature...facing the scenic Sea of Japan, the Hodatsu mountain range, the Kahokudai sand dunes, the Kahokugata Lagoon, and the Omigawa River”, below the title, it reads “welcome to our city, nestled between green splendor and the sea”.
When I asked him if his interest in the ocean had anything to do with him growing up so close to it, he thought about it for a moment, “well, I remember my parents took me snorkeling a few times”, but the feeling, as he put it ,“of being connected to the sea”, that started in his early twenties when a friend who he played baseball with introduced him to surfing. “Yeah, that was what really brought me closer to the ocean”.
Now, Terauchi researches the application of ocean color remote sensing for monitoring and assessment of eutrophication. Research he began while doing a PhD at Nagasaki University under the supervision of Dr. Joji Ishizaka - a pioneer in Japan, on the use of ocean color remote sensing to study the ocean. When he speaks of Dr. Ishizaka - whom he met after he had started working with NPEC - it is with a type of reverence. “I’m really lucky that I met him” he told me. At the time, Dr. Ishizaka was studying water quality in Toyama bay and encouraged Terauchi to apply for his PhD which ended up taking seven and a half years to complete.
Eutrophication is a major problem in the Northwest Pacific region, which is where Terauchi conducts his research. In fact, according to a report recently published by CEARAC, eutrophication, along with habitat alteration and non-indigenous species have been identified as the major threats to marine biodiversity in the region. While there are various anthropogenic drivers of these threats that have been identified, aqualcutlure - which has been linked to all three, is increasingly being recognized as playing a significantly strong role, which makes sense considering the region now has one of the most active sea area aquaculture operations in the world.
It is incredibly important that we remain aware of the status of eutrophication, so that we can determine how, where and when to intervene. “One way of doing this is water sampling” he explained, “but this is costly, and anyways, so many people are already doing it”. He believes that blending multiple ocean color sensors to get a long-term data set is a much more effective way of monitoring and assessing eutrophication. Another area of work he is involved in is using remote sensing to map sea grass. A project Lev Neretin - senior coordinator of the North West Pacific Action Plan’s Regional Coordinating unit (NOWPAP RCU) - has described as, “ truly pioneering work in the region”.
Seagrasses don’t really receive as much attention as they should be considering that they are some of the most productive ecosystems on the globe, providing vital habitats and nursery grounds for a multitude of species, such as sea urchins, crabs, sea cucumbers, starfish, plus other recreational and commercial fish species. They improve water quality and clarity by trapping sediment and filtering excess nutrients. They provide food for grazers such as turtles, dugongs and manatees, and they are also incredibly important sites for carbon storage.
It is in regard to the latter that seagrass is beginning to find a spotlight under a number of global initiatives and projects. For instance, the Blue Forests Project, a four-year project initiated by the United Nations Environment programme and funded and financed by the Global Environment Facility and GRID-Arendal respectively - which hopes to fill in gaps on the value of these carbon sequestration systems. And the International Blue Carbon Initiative that is focusing on the conservation and restoration of coastal and marine ecosystems as a way of mitigating the impacts of climate change.
Seagrasses, however, cannot be protected if we don’t know where they are. This makes all our attempts to map them especially crucial, but, mapping seagrass using remote sensing is not as straightforward as trying to map for example, terrestrial features, or things easily visible on the ocean surface. “Those things are easy to detect with satellite sensors, but once it’s under the water its a little more complicated. You need to work a lot on correcting images before you analyze” he explained “for example, sometimes the sea surface is not very smooth, when the wind blows it creates roughness it bothers analysis of the images. Some images have strong reflections of light or some images are just cloudy”.
In fact, until now, one of the biggest barriers has been trying to find out how to cut down on the time and labor required to correct and analyze the images. “There are many techniques to do this and there are scientists who are working on only this - image correction!” he told me, such as atmospheric correction, which removes disturbances caused by the atmosphere that then get picked up by the satellite sensors, or water column correction, that has to do with how different information is picked up by the sensors depending on the depth the object is situated at.
Now, CEARAC uses various algorithms for correcting satellite images. “Before” he said, “ I was just using my eyes to do that screening”, but then he added, they carried out a study to see how much time and labor it would take to map the distribution of seagrass in just one small Japanese bay using conventional methods of analysis, which required buying the images from private satellite operators, collecting existing field data, preparing training data sets, applying corrections as necessary, classifying images and assessing the accuracy of the obtained classification results. They concluded that trying to map the whole Northwest pacific using this method would be nearly impossible.
“So, I googled it” he said laughing, “yeah, you’re in trouble - you google!”. This was how Terauchi came aross the study by Hansen et al. (2013), High-Resolution Global Maps of 21st-Century Forest Cover Change, that mapped global forest change over a 12 year period using data at a 30-meter spatial resolution. “I was really shocked to know that that was possible” he said flashing a wide grin “I was just looking at the nowpap sea are but theres a guy who’s done forest mapping for the whole earth, I said what kind of technique is he using and turns out he was using a tool called Google Earth Engine”.
Google Earth Engine, as is described on their website, “combines a multi-petabyte catalog of satellite imagery and geospatial datasets with planetary-scale analysis capabilities and makes it available for scientists, researchers, and developers to detect changes, map trends, and quantify differences on the Earth's surface”. Basically, a process that would have taken decades of work to complete, could now potentially be done in just a few days, and for little to no cost. “I thought ok maybe we can do something similar for mapping sea grass, and thats what we are working on right now”.
Other researchers are already looking into seagrass mapping using remote sensing though, Terauchi explained, like Nasa and WWF Germany, “we share information”. When I asked him if he thought, from what he had seen, that seagrass in the Northwest Pacific region was healthy, he replied that it really depended on the place. “A lot of habitats have been lost by coastal development. Not much is documented but im pretty sure”.
There is still a lot that remains in obscurity when it comes to seagrass, academically and with the general public. I asked Terauchi if he felt that there was a growing awareness on the importance of seagrass in the region and he replied with a resounding no! And then as if anticipating my next question he added, “especially fishermen” who ironically see the seagrass as a hinderance to their fishing activities, particularly when it gets tangled up in their equipment. When I asked him if he thought we were at least moving in that direction, he nodded and said, “well, it’s necessary”.
We did not really talk much about the other two threats being studied by CEARAC, non-invasive species and habitat-alteration. The latter came up occasionally regarding its strong link to both eutrophication and the loss of seagrass meadows, but then also, in a rather more personal and profound way. Several years ago, the seafloor of Kanazawa harbor was dredged to accommodate the passage of big ships, the sand that had been dug out, it was decided, would be relocated to Kanaiwa beach. While a group of surfers - familiar with Terauchi - attempted to protest this development through a signed petition, the project, regretfully, went on as planned.
While dredging can have its benefits, it can also be incredibly harmful to the marine environment. It can change the composition of the soil, introduce or spread contaminants - unfavorably altering the habitats of small organisms that live down on the seabed where it is easy to ignore them, and the role they play in the complicated web which supports our own lives. But it also changes things that are more immediately tangible, and therefore easier to love, especially by those communities that hold a unique knowledge of, and significantly more meaningful connection to the seas than in reality, most of us - the very type of people we need if we are to keep our oceans alive - things such as, for example, the distinct shape of a wave.
Terauchi told me that after the Kanaiwa beach incident, he was watching the surf movie Sprout by the film maker Thomas Campbell, and was inspired by the scene on Tom Wegener (renowned for hand-crafting surfboards using Paulownia wood), to start making his own wooden surfboards, something he has been doing for a while now. “I wanted to do something different” he said, referring to what had happened, “it’s easy to say but I wanted to deliver a message...that people need to pay more attention to environmental changes upstream, because those changes also influence marine and coastal environments below” and then he added cheerily, “my goal now is to make environmentally friendly surfboards using less chemicals and only locally sourced wood!”
9-11 Oct. Twenty-third Intergovernmental Meeting | Moscow, Russian Federation
29-30 Oct. Our Ocean Conference 2018 | Bali, Jakarta Raya, Indonesia
25 Oct. - 4 Nov. PICES-2018 Annual Meeting: Toward Integrated Understanding of Ecosystem Variability in the North Pacific | Yokohama, Japan
31 Oct. – 1 Nov. Fourth Intergovernmental Review Meeting on the Implementation of the Global Programme of Action for the Protection of the Marine Environment from Land-based Activities (GPA) | Bali, Jakarta Raya, Indonesia
26-28 Nov. Sustainable Blue Economy Conference | Nairobi, Kenya
27-30 Nov. The East Asian Seas Congress 2018 | Iloilo City, Philippines
5-9 Jan. Regional Consultative Meeting: Asia Pacific | Pulau Ujong, Island, Singapore
11-15 March Fourth session of the UN Environment Assembly (UNEA-4) | Nairobi, Kenya
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